Electronic component including a surface acoustic wave element and a pillar member

Abstract

An electronic component includes a support layer that surrounds an element region on a principal surface of a piezoelectric substrate, when viewed in plan from a z-axis direction. A surface acoustic wave element is provided in the element region. A cover layer is provided on the support layer, and is opposed to the principal surface. A pillar member connects the principal surface and the cover layer in a space surrounded by the principal surface, the support layer, and the cover layer, and does not contact with the support layer.

What is claimed is: 
     
       1. An electronic component comprising:
 a substrate; 
 a support layer that surrounds a predetermined region on a principal surface of the substrate, when viewed in plan from a normal direction of the principal surface; 
 a surface acoustic wave element provided in the predetermined region; 
 a cover layer provided on the support layer and opposed to the principal surface; 
 a pillar member that connects the principal surface and the cover layer in a space surrounded by the principal surface, the support layer, and the cover layer and that does not contact with the support layer; and 
 a first via hole conductor extending in the pillar member in the normal direction of the principal surface; wherein 
 the pillar member is mad of resin. 
 
     
     
       2. The electronic component according to  claim 1 , further comprising:
 a trace connected to the first via-hole conductor and provided on the principal surface; and 
 an external connecting portion to which a ground potential is applied, the external connecting portion being connected to the first via-hole conductor and provided on a portion of the cover layer directly on the first via-hole conductor. 
 
     
     
       3. The electronic component according to  claim 2 , wherein the external connecting portion is defined by at least one conductive bump. 
     
     
       4. The electronic component according to  claim 1 , wherein the support layer and the pillar member are made of a same material. 
     
     
       5. The electronic component according to  claim 1 , wherein the cover layer includes:
 a first cover layer provided on the support layer and made of a material different from a material of the support layer; and 
 a second cover layer provided on the first cover layer and made of a same material as the material of the support layer. 
 
     
     
       6. The electronic component according to  claim 5 , wherein the second cover layer and the support layer are made of a water-resistance insulating material. 
     
     
       7. The electronic component according to  claim 5 , wherein the first cover layer bonds the support layer and the second cover layer. 
     
     
       8. The electronic component according to  claim 1 , wherein the surface acoustic wave element defines a surface acoustic wave filter. 
     
     
       9. The electronic component according to  claim 1 , wherein a plurality of the surface acoustic wave elements are provided in the predetermined region. 
     
     
       10. The electronic component according to  claim 1 , wherein the pillar member is provided at a center or substantially at the center of the principal surface. 
     
     
       11. The electronic component according to  claim 10 , further comprising:
 a second via-hole conductor extending in the support layer in the normal direction of the principal surface; wherein 
 a cross-sectional area of the first via-hole conductor along a plane parallel or substantially parallel to the principal surface is larger than a cross-sectional area of the second via-hole conductor along the plane parallel or substantially parallel to the principal surface. 
 
     
     
       12. The electronic component according to  claim 1 , wherein the substrate is a piezoelectric substrate that is rectangular or substantially rectangular plate shaped and is one of a quartz substrate, an LiTaO 3  substrate, an LiNbO 3  substrate, and a substrate with a ZnO thin film. 
     
     
       13. The electronic component according to  claim 1 , wherein the predetermined region is an area on the principal surface excluding portions near corners and sides thereof. 
     
     
       14. The electronic component according to  claim 1 , wherein the support layer includes a frame portion and a plurality of projections. 
     
     
       15. The electronic component according to  claim 1 , wherein the pillar member is a cylindrical or substantially cylindrical insulating body. 
     
     
       16. The electronic component according to  claim 1 , further comprising a plurality of conductive pads aligned with projections of the support layer and arranged to be connected to via hole conductors. 
     
     
       17. The electronic component according to  claim 1 , wherein the surface acoustic wave element includes a plurality of surface acoustic wave resonators arranged to define a ladder circuit. 
     
     
       18. The electronic component according to  claim 1 , wherein the surface acoustic wave element defines a resonator having resonant characteristics at a resonant frequency determined by a pitch of comb-shaped electrodes thereof. 
     
     
       19. A circuit module comprising:
 a circuit board; 
 a plurality of lands on the circuit board; 
 the electronic component according to  claim 1  mounted on the circuit board via the plurality of lands; and 
 a resin cover arranged on the circuit board to cover the electronic component.